Brain oxytocin receptors mediate ejaculation elicited by 7-hydroxy-2-(di-N-propylamino) tetralin (7-OH-DPAT) in anaesthetized rats

BACKGROUND AND PURPOSE

The involvement of the neuropeptide oxytocin in the control of male sexual responses is documented although its exact mechanisms of action, and especially the site(s) of action, are not fully delineated. In order to clarify this issue, we tested the effects of a peptide oxytocin antagonist delivered through different routes on sexual responses elicited, in anaesthetized male rats, by i.c.v. 7-hydroxy-2-(di-N-propylamino) tetralin (7-OH-DPAT), a dopamine agonist, preferentially active on D3 receptors.

EXPERIMENTAL APPROACH

Seminal vesicle pressure (SVP) and bulbospongiosus muscle (BS) electromyograms were recorded as physiological markers of emission and expulsion phases of ejaculation respectively and intracavernosal pressure (ICP) was monitored as a physiological marker of erection.

KEY RESULTS

When injected i.v., the oxytocin antagonist did not impair 7-OH-DPAT-induced SVP and ICP responses while BS burst frequency was diminished. When delivered i.c.v., the oxytocin antagonist dose-dependently inhibited occurrence of 7-OH-DPAT-induced sexual responses. When delivered intrathecally (i.t.) at the level of the 6th lumbar (L6) segment, but not the 13th thoracic (T13) segment, the oxytocin antagonist reduced the duration of BS responses and the occurrence of ejaculation without impairing ICP responses.

CONCLUSIONS AND IMPLICATIONS

Brain oxytocin receptors mediate male sexual responses elicited by i.c.v. 7-OH-DPAT in anaesthetized rats whereas L6 spinal oxytocin receptors only impair the occurrence of ejaculation. Peripheral oxytocin receptors are marginally involved in 7-OH-DPAT-induced sexual responses. These findings should be considered for the development of potential pharmacological treatment of premature ejaculation in man.

Cardiovascular outcomes among sildenafil users: results of the International Men's Health Study

AIM

To assess the incidence of serious cardiovascular disease (CVD) events [i.e. myocardial infarction (MI) and stroke] and all-cause mortality in men with erectile dysfunction (ED) who received prescriptions for sildenafil.

METHODS

The International Men's Health Study (IMHS) was a prospective, observational cohort study of patients with ED and a new or existing prescription for sildenafil. Baseline and follow-up questionnaires provided information on demographics, CVD risk factors and ED. Postevent questionnaires were mailed to patients following possible nonfatal CVD events to collect information related to exposure to sildenafil/ED treatments before the event.

RESULTS

Thirty-five CVD events were reported in 30 patients in the analysis set (n = 3813). The incidence of all-cause mortality, MI and stroke was 0.4, 0.6 and 0.1 per 100 patient-years of observation respectively. Among the six men who reported using sildenafil in the month before a nonfatal CVD event, two reported use in the 24 h before the event.

CONCLUSION

The results of the IMHS support previous reports that ED and CVD are often comorbid and share risk factors.

The three stages of epilepsy in patients with CDKL5 mutations

Mutations in the X-linked cyclin-dependent kinase-like 5 (CDKL5) gene are responsible for a severe encephalopathy with early epilepsy. So far, the electroclinical phenotype remains largely unknown and no clear genotype-phenotype correlations have been established.

PURPOSE

To characterize the epilepsy associated with CDKL5 mutations and to look for a relationship between the genotype and the course of epilepsy.

METHODS

We retrospectively analyzed the electroclinical phenotypes of 12 patients aged from 2.5 to 19 years diagnosed with pathogenic CDKL5 mutations and one patient with a novel intronic sequence variation of uncertain pathogenicity and examined whether the severity of the epilepsy was linked to the type and location of mutations.

RESULTS

The epilepsy course reveals three successive stages: (Stage I) early epilepsy (onset 1-10 weeks) with normal interictal electroencephalogram (EEG) (10/13) despite frequent convulsive seizures; (Stage II) epileptic encephalopathy with infantile spasms (8/8) and hypsarrhythmia (8/8). At the age of evaluation, seven patients were seizure free and six had developed refractory epilepsy (stage III) with tonic seizures and myoclonia (5/6). Interestingly, the patients carrying a CDKL5 mutations causing a truncation of the catalytic domain tended to develop a more frequent refractory epilepsy than patients with mutations located downstream (4/6, 66.6% versus 1/6, 16%) although, these trends are not yet significant.

DISCUSSION

Our data contribute to a better definition of the epileptic phenotype in CDKL5 mutations, and might give some clues to a potential relationship between the phenotype and the genotype in these patients.

Acrocallosal syndrome in fetus: focus on additional brain abnormalities

Acrocallosal syndrome (ACS) is an autosomal recessive disorder characterized by craniofacial dysmorphism, agenesis or hypoplasia of the corpus callosum, duplication of the phalanges of the hallux, more rarely the thumbs, post-axial polydactyly, syndactyly and severe mental retardation. Here we report the two first descriptions of acrocallosal syndrome in fetus with extensive neuropathological study and provide new data regarding additional brain abnormalities in ACS. The first case was a 25-gestational week male fetus displaying craniofacial and limb abnormalities, with bilateral syndactyly of the fourth and fifth fingers, preaxial polydactyly of the left foot and an inter-frontal extra-bone. The second fetus was a 33-gestational week male fetus. His left hand displayed a broad thumb and 4/5 syndactyly. In both cases, gross examination of the brain showed an absence of corpus callosum associated with interhemispheric cysts. The cerebral cortex in front of the cysts was nodular. Upon microscopic examination, the nodular masses corresponded to large dysplastic areas represented by clusters of undifferentiated neurons in the white matter. The cyst wall showed arachnoidal and ependymal covering and contained numerous choroid plexus, suggesting a developmental abnormality of the ventricles. The pons and the cerebellum were hypoplastic. The dentate nuclei were fragmented. Numerous neuronal heterotopias associated with ectopic ependymal cavities were observed in the vermis in one case. The olivary nuclei were severely dysplastic too. We hope that these new data will make both the ante- and post-natal diagnosis easier, facilitate comparisons with animal models and encourage the identification of the genes responsible for this syndrome.

Urethral closure mechanisms during sneezing-induced stress in anesthetized female cats

During stress-induced increase in abdominal pressure, urinary continence is maintained by urethral closure mechanisms. Active urethral response has been studied in dogs and rats. Such an active urethral response is also believed to occur in humans during stress events. We aimed to investigate urethral closure mechanisms during sneezing in cats. Urethral pressures along the urethra (UP1-UP4), with microtip transducer catheters with UP4 positioned in the distal urethra where the external urethral sphincter (EUS) is located, and intravesical pressure were measured, and abdominal wall, anal sphincter (AS), levator ani (LA), and EUS electromyograms (EMGs) were recorded during sneezing under closed-abdomen and open-abdomen conditions in eight anesthetized adult female cats. Proximal and middle urethral response induced by sneezing was not different from bladder response. Distal urethral response was greater compared with proximal and middle urethral and bladder response. In the open-abdomen bladder, proximal and middle urethral responses were similarly decreased and distal urethral response was unchanged compared with the closed-abdomen bladder. Bladder and urethral responses were positively correlated to sneeze strength. EUS, LA, and AS EMGs increased during sneezing. No urine leakage was observed, regardless of the strength of sneeze. In cats urethral closure mechanisms are partly passive in the proximal and middle urethra and involve an active component in the distal urethra that is believed to result from EUS and possibly LA contractions. Because central serotonin exerts similar effects on the lower urinary tract in cats and humans, the cat may represent a relevant model for pharmacological studies on continence mechanisms.

Further evidence of the reliability and validity of the premature ejaculation diagnostic tool

This study details the further validation of the Premature Ejaculation Diagnostic Tool (PEDT), a five-item tool, developed to systematically apply the Diagnostic and Statistical Manual of Mental Disorders, revised version 4 (DSM-IV-TR), criteria in diagnosing presence or absence of premature ejaculation (PE). A total of 102 men completed the PEDT and were then interviewed by one of the seven clinical experts, who made a diagnosis of presence or absence of PE. The diagnoses from these two methods were compared to assess the convergent validity of PEDT. Retest reliability was also assessed, by men completing the PEDT a second time, approximately 2 weeks after the first administration. The level of agreement between clinical expert and PEDT diagnoses was very high (kappa-statistic=0.80 (95% CI=0.68-0.92)), and retest reliability was very good - Intraclass correlation coefficient=0.88. In summary, the PEDT is extensively validated, self-report measure that can systematically assess DSM-IV-TR criteria to provide accurate diagnoses of PE/no-PE.

Chapitre A - Les dysfonctions sexuelles masculines et leurs traitements en neuro-urologie

The management of sexual dysfunction has been revolutionized over recent years with the arrival of new treatments for erectile dysfunction. In parallel, groups specialized in neurosexology have gradually emerged in order to improve the patient's fertility. This article presents the disorders most frequently encountered in spinal cord injury and the main approaches to management.

Chapitre A-2 - Traitements pharmacologiques per-os à visée sphinctérienne en neuro-urologie

Sphincter dysfunction is an almost constant pathological process in neurourology. No oral pharmacological treatment is available to treat stress urinary incontinence secondary to sphincter incompetence or to relieve urethral hypertonia usually induced by detrusor-sphincter dyssynergia. The few treatments that induce sphincter relaxation are not sufficient to justify a routine therapeutic indication.

Effect of acute dapoxetine administration on the pudendal motoneuron reflex in anesthetized rats: comparison with paroxetine

PURPOSE

Pudendal motoneuron reflex discharges elicited by bilateral electrical stimulation of the dorsal nerves of the penis were used as an experimental model of the expulsion reflex of ejaculation to investigate the effect of acute intravenous delivery of dapoxetine, a short acting selective serotonin reuptake inhibitor, in anesthetized rats. Dapoxetine was compared with paroxetine, the selective serotonin reuptake inhibitor of reference.

MATERIALS AND METHODS

Stimulating electrodes were placed bilaterally on the dorsal nerves of the penis and a recording electrode was placed on the motor branch of the pudendal nerve to monitor pudendal motoneuron reflex discharges in urethane anesthetized rats. Pudendal motoneuron reflex discharges induced by penile dorsal nerve stimulation were measured before and 60 minutes after a single intravenous injection of dapoxetine or paroxetine, each tested at 3 doses (1, 3 and 10 mg/kg) or after a single injection of vehicle.

RESULTS

At all doses tested dapoxetine significantly lengthened the latency of pudendal motoneuron reflex discharges following bilateral stimulation of the dorsal nerves of the penis in comparison with vehicle, whereas only the 1 mg/kg dose of paroxetine was effective. The amplitudes of pudendal motoneuron reflex discharges were significantly decreased only in rats treated with 3 mg/kg dapoxetine compared to vehicle.

CONCLUSIONS

Acute systemic delivery of selective serotonin reuptake inhibitors is capable of modulating the expulsion reflex of ejaculation in anesthetized rats with dapoxetine appearing to be more effective than paroxetine. These findings support the beneficial effect of on-demand administration of dapoxetine for premature ejaculation.

Mutations in PHD-like domain of the ATRX gene correlate with severe psychomotor impairment and severe urogenital abnormalities in patients with ATRX syndrome

Mutations in ATRX are associated with a wide and clinically heterogeneous spectrum of X-linked mental retardation syndromes. The ATRX protein, involved in chromatin remodelling, belongs to the family of SWI/SNF DNA helicases and contains a plant homeodomain (PHD)-like domain. To date, more than 60 different mutations have been reported in ATRX. One of them is recurrent and accounts for 20% of all the reported mutations, whereas all others are private. Most mutations are clustered in the two major functional domains, the helicase and the PHD-like domain. So far, no clear genotype-phenotype correlation has been established, with exception to the rare truncating mutations located at the C-terminal part of the protein, which are consistently associated with severe urogenital defects. In this study, we report the molecular analysis performed in 16 families positive for ATRX. Our findings indicate that, in addition to the previously described mutation 'hotspot' in the PHD-like domain, two other protein sections emerge as minor 'hotspots' in the helicase region encoded by exons 18-20 and 26-29, respectively, gathering 33% of all described mutations. Additionally, based on the clinical data collected for 22 patients from the 16 families, we observe that mutations in the PHD-like domain produce severe and permanent psychomotor deficiency, usually preventing patients from walking, as well as constant urogenital abnormalities, while mutations in the helicase domain lead to delayed but correct psychomotor acquisitions together with mild or absent urogenital abnormalities. In summary, mutations in the helicase domain are associated with milder phenotypes than mutations in the PHD-like domain.

Unbalanced inherited complex chromosome rearrangement involving chromosome 8, 10, 11 and 16 in a patient with congenital malformations and delayed development

Complex chromosome rearrangements (CCR) are rare structural chromosome aberrations that can be found in patients with phenotypic abnormalities or in phenotypically normal patients presenting, however, recurrent miscarriages or infertility. Conventional karyotype generally allows their identification. However, molecular cytogenetic methods can reveal subtle rearrangements. We report, here, the identification of an unbalanced maternally inherited CCR in a boy with multiple congenital malformations and delayed development. High-resolution karyotype completed by molecular cytogenetic prompted us to precise the rearrangements. The healthy mother was found to carry a balanced de novo CCR that implicates four chromosomes (8, 10, 11 and 16), six breakpoints, three translocations and an insertion. The malsegregation of this CCR had led, in her son, to partial 10p12.3 to 10p14 deletion, a chromosomal region associated with the DiGeorge like phenotype.

Efficacy and safety of vardenafil in men with erectile dysfunction caused by spinal cord injury

OBJECTIVE

To assess the efficacy and tolerability of vardenafil in men with erectile dysfunction (ED) due to traumatic spinal cord injury (SCI).

METHODS

In this multicenter, double-blind, placebo-controlled, parallel-group 12-week study, 418 men aged 18 years and older with ED for more than 6 months consequent to SCI were randomized to vardenafil (n = 207) or placebo (n = 211) (10 mg for 4 weeks, then maintained or titrated to 5 or 20 mg at weeks 4 and 8). Efficacy assessments included the erectile function (EF) domain score of the International Index of Erectile Function questionnaire and diary questions regarding penetration, maintenance of erection to completion of intercourse, and ejaculation.

RESULTS

Baseline patient characteristics were similar in the vardenafil (mean age 40 years) and placebo (mean age 39 years) groups. Mean baseline EF domain scores were 11.6 in the vardenafil group and 12.1 (moderate ED) in the placebo group. EF domain score in the vardenafil group improved to 22.0 (mild ED) at last observation carried forward vs 13.5 in the placebo group (p < 0.001). Over 12 weeks of treatment, mean per-patient penetration (76% vs 41%), maintenance (59% vs 22%), and ejaculation (19% vs 10%) success rates were significantly greater vs placebo (all p < 0.001). The most frequently reported drug-related adverse events were headache (vardenafil 15%, placebo 4%), flushing (vardenafil 6%, placebo 0%), nasal congestion (vardenafil 5%, placebo 0%), and dyspepsia (vardenafil 4%, placebo 0%).

CONCLUSION

Vardenafil significantly improved erectile and ejaculatory function and was generally well tolerated in men with erectile dysfunction due to spinal cord injury.

Identification of lumbar spinal neurons controlling simultaneously the prostate and the bulbospongiosus muscles in the rat

Lumbar spinothalamic neurons in the lamina X of the L3-L4 spinal cord segment have been proposed to constitute the spinal ejaculation generator in male rats. Lumbar spinothalamic cells are immunoreactive for galanin and neurokinin-1 receptors. We previously showed that after injection of pseudorabies virus either in the bulbospongiosus muscle or in the prostate, retrogradely labeled cells in the L3-L4 segment also displayed galanin or neurokinin-1 receptor immunoreactivities, demonstrating a direct link between lumbar spinothalamic cells and two anatomical structures involved in the two phases of ejaculation i.e. the emission and the expulsion phases. In order to provide with a more precise anatomical support for the role of lumbar spinothalamic cells in controlling ejaculation, we injected simultaneously in male adult rats two strains of recombinant pseudorabies virus, expressing either beta-galactosidase (PRV-BaBlu) or green fluorescent protein (PRV-152) in the prostate and in the bulbospongiosus muscle, respectively. After 5 days, we performed multiple immunofluorescence experiments to detect PRV-BaBlu, PRV-152 and galanin or neurokinin-1 receptors in transverse sections of the L1-S1 segment. Double- and triple-labeled cells were counted using confocal laser scanning microscope. Double-labeled neurons with the two strains of pseudorabies virus were mainly found at the L3-L4 segment lateral to the central canal in lamina X and represented about 60% of the total number of pseudorabies virus-labeled neurons. All the double pseudorabies virus-labeled neurons also expressed lumbar spinothalamic and most of them neurokinin-1 receptor, identifying them as lumbar spinothalamic neurons. The convergence of retrograde labeling from prostate and bulbospongiosus muscle on the same lumbar spinothalamic cells strongly reinforce their role in the spinal control and coordination of the emission and expulsion of sperm.

Melanotan-II: Investigation of the inducer and facilitator effects on penile erection in anaesthetized rat

The effects of melanotan-II, a non-specific agonist of melanocortin receptors, on erection and its possible sites of action were investigated in anesthetized rats. Delivered i.v. (0.1, 0.3 and 1 mg/kg) or within the paraventricular nucleus of the hypothalamus (0.1 and 1 microg), melanotan-II exerted a dose-dependent inducer activity on erection by eliciting erectile events and shortening latency of the first erectile event to occur. Erectile events were of higher amplitude in rats treated with melanotan-II i.t. (0.2 microg) delivered at the L6-S1 level than in animals treated with the vehicle i.t. delivered. Erectile responses elicited by cavernous nerve stimulation were increased after i.v. melanotan-II (1 mg/kg), thereby exerting facilitator effect on erection. In contrast, melanotan-II injected within the corpus cavernosum (1 microg) did not display any facilitator activity. To investigate the neural pathways involved in the facilitator effect of melanotan-II, we performed acute spinalization (T8 level) and differential selective nerve transections. Neither spinalization nor bilateral transection of pelvic nerves or dorsal penile nerves impaired facilitator activity of i.v. melanotan-II (1 mg/kg). Conversely, the facilitator effect of melanotan-II was abolished after acute removal of the lumbar paravertebral sympathetic chain. These results lead to the conclusion that central and peripheral melanocortin pathways are recruited by melanotan-II, depending on its route of delivery, to exert both inducer and facilitator activities on erection.

[ATR-X syndrome: a new mutation in the XNP/ATRX gene near the helicase domain]

The alpha-thalassemia/mental retardation syndrome, X linked, also named ATR-X syndrome is a X-linked mental retardation syndrome. Mutations have been found in the ATRX gene in about one half of the patients. We report a typical clinical case. The clinical evidence leads us to continue the analysis of the gene despite a negative first screening. Indeed a new mutation was found, just behind the helicase domain, bringing up the interest of an effective collaboration between physicians and biologists.

The Use of Telemetry Technology to Test the Proerectile Effect of Melanotan-II (MT-II) in Conscious Rats

OBJECTIVE

The aim of this study is to demonstrate that monitoring, by means of telemetry technology, the increases in intracavernosal pressure (ICP) in freely moving rats using melanotan-II (MT-II) as a proerectile inducer compound is a relevant experimental model to investigate the effects of pharmacological agents on erection.

METHODS

Adult rats were implanted in the corpus cavernosum with a pressure sensor which permitted telemetric monitoring of ICP in freely moving animals following MT-II (0.1, 0.3 and 1 mg/kg) or saline i.v. injections. ICP was also measured after MT-II (0.1, 0.3 or 1 mg/kg) or saline i.v. delivery in anesthetized rats.

RESULTS

In conscious rats, MT-II (1 mg/kg) significantly increased overall erectile activity compared to saline. In anesthetized rats, MT-II-induced increase in overall erectile activity was not statistically significant but displayed a similar pattern.

CONCLUSIONS

The use of telemetry technology allowed to collect quantifiable and reliable data regarding the proerectile activity of MT-II in physiological conditions. The telemetry model appears suitable for investigating the potential inducer proerectile properties of pharmacological agents.

Piboserod (SB 207266), a selective 5-HT4 receptor antagonist, reduces serotonin potentiation of neurally-mediated contractile responses of human detrusor muscle

The aim of this study is to evaluate the potency of piboserod (SB 207266), a selective 5-HT(4) receptor antagonist, at inhibiting the 5-HT(4)-mediated potentiating effect of serotonin (5-HT) on the neurally-mediated contractile responses of human detrusor strips to electrical field stimulations (EFS). Strips of human detrusor muscle were mounted in Krebs-HEPES buffer under a resting tension of 500 mg and EFS (20 Hz, 1 ms duration at 300 mA for 5 s) was applied continuously at 1 min intervals. After stabilization of the EFS-induced contractions, concentration-response curves to 5-HT (0.1 nM-100 microM) were constructed in the absence or presence of 1 or 100 nM of piboserod. The experiments were performed in the presence of methysergide (1 microM) and ondansetron (3 microM) to block 5HT(1)/5HT(2) and 5-HT(3) receptors, respectively. 5-HT potentiated the contractile responses to EFS of human bladder strips in a concentration-dependent manner, with a maximum mean of 60.0+/-19.9% of the basal EFS-evoked contractions. Piboserod did not modify the basal contractions but concentration-dependently antagonized the ability of 5-HT to enhance bladder strip contractions to EFS. In presence of 1 and 100 nM of piboserod, the maximal 5-HT-induced potentiations were reduced to 45.0+/-7.9 and 38.7+/-8.7%, respectively. A mean apparent antagonist dissociation constant value (K(B)) of 0.56+/-0.09 nM was determined. These data show the ability of piboserod to antagonize with high potency the enhancing properties of 5-HT on neurally-mediated contractions of isolated human bladder strips. Therefore, the 5-HT(4) receptor might represent an attractive pharmacological target for the treatment of overactive bladder.

Loss of ZMPSTE24 (FACE-1) causes autosomal recessive restrictive dermopathy and accumulation of Lamin A precursors

Restrictive dermopathy (RD) is characterized by intrauterine growth retardation, tight and rigid skin with prominent superficial vessels, bone mineralization defects, dysplastic clavicles, arthrogryposis and early neonatal death. In two patients affected with RD, we recently reported two different heterozygous splicing mutations in the LMNA gene, leading to the production and accumulation of truncated Prelamin A. In other patients, a single nucleotide insertion was identified in ZMPSTE24. This variation is located in a homopolymeric repeat of thymines and introduces a premature termination codon. ZMPSTE24 encodes an endoprotease essential for the post-translational cleavage of the Lamin A precursor and the production of mature Lamin A. However, the autosomal recessive inheritance of RD suggested that a further molecular defect was present either in the second ZMPSTE24 allele or in another gene involved in Lamin A processing. Here, we report new findings in RD linked to ZMPSTE24 mutations. Ten RD patients were analyzed including seven from a previous series and three novel patients. All were found to be either homozygous or compound heterozygous for ZMPSTE24 mutations. We report three novel 'null' mutations as well as the recurrent thymine insertion. In all cases, we find a complete absence of both ZMPSTE24 and mature Lamin A associated with Prelamin A accumulation. Thus, RD is either a primary or a secondary laminopathy, caused by dominant de novo LMNA mutations or, more frequently, recessive null ZMPSTE24 mutations, most of which lie in a mutation hotspot within exon 9. The accumulation of truncated or normal length Prelamin A is, therefore, a shared pathophysiological feature in recessive and dominant RD. These findings have an important impact on our knowledge of the pathophysiology in Progeria and related disorders and will help direct the development of therapeutic approaches.

Galanin and neurokinin-1 receptor immunoreactivity spinal neurons controlling the prostate and the bulbospongiosus muscle identified by transsynaptic labeling in the rat

Ejaculation requires the coordination of sympathetic, parasympathetic and somatic neural outputs. Timely occurrence of the emission and expulsion of sperm results from an interplay between spinal nuclei innervating the seminal tract and the sexual accessory glands including the prostate on the one hand, and on the other hand perineal striated muscles, particularly the bulbospongiosus muscle. A group of cells essential for ejaculation, located around the central canal and referred to as lumbar spinothalamic neurons have been recently identified. Lumbar spinothalamic neurons are immunoreactive for galanin and neurokinin-1 receptor. In order to investigate the anatomical relationships between lumbar spinothalamic neurons and both the prostate and the bulbospongiosus muscle, pseudorabies virus retrograde tracing technique was used combined with immunohistochemistry. Three to five days after pseudorabies virus injection in the bulbospongiosus muscle or the prostate in male rats, spinal cord sections were processed for double immunofluorescence against pseudorabies virus and galanin or neurokinin-1 receptor. Immunocytochemical experiments against pseudorabies virus and choline acetyltransferase were also performed to discriminate between motoneurons and preganglionic neurons, or interneurons. Spinal sections were examined with confocal laser scanning microscope. Three days after pseudorabies virus injection within the prostate and the bulbospongiosus muscle, sympathetic preganglionic neurons and motoneurons of the dorsomedial nucleus were retrogradely labeled, respectively. Five days after pseudorabies virus injection, transsynaptically labeled choline acetyltransferase-negative neurons were found mainly located in the medial gray surrounding the central canal from L1 to S1. At the L3-L4 level, most of transsynaptically labeled neurons were immunoreactive for galanin and to a lesser extent for neurokinin-1 receptor, strongly suggesting that they could be the lumbar spinothalamic cells. We have thus evidenced connections between these cells and motoneurons of the dorsomedial nucleus and both sympathetic and parasympathetic preganglionic neurons innervating the bulbospongiosus muscle and the prostate, respectively. These anatomical data reinforce the crucial role for lumbar spinothalamic cells in coordinating the spinal control of ejaculation.

The ‘effectiveness’ scale—therapeutic outcome of pharmacologic therapies for ED: an international consensus panel report

Despite availability of outcome measures and scales for assessing erectile dysfunction (ED) treatment efficacy, guidelines are not available for assessing broader therapeutic outcomes or defining treatment failure in ED. An International Consensus Advisory Panel was convened to develop guidelines, definitions and a new algorithm for evaluating treatment effectiveness in ED. These new guidelines are recommended for use in both research and clinical practice. A multidisciplinary, international panel, consisting of 11 senior researchers and clinicians, was convened to address pertinent issues concerning therapeutic outcome assessment for ED. The panel utilized a modified Delphi method of consensus development and proposed a new model for outcomes assessment. This model is inherently testable, using existing instruments and current methods of assessment. Following a comprehensive literature review and discussion, the Panel recommended adoption of a new treatment effectiveness conceptual framework or theoretical model for assessing therapeutic outcomes in ED. Treatment effectiveness is presumed to be a combined function of two other factors, treatment response and treatment satisfaction. Treatment response is based on the combined assessment of efficacy and tolerability, and treatment satisfaction on the combined assessment of patient and partner satisfaction. Taken together, these two domains define an overall domain of treatment effectiveness. This therapeutic index would be derived by independently assessing treatment efficacy and satisfaction by means of event logs, questionnaires or the more typical patient interview methods. In conclusion, the Ad Hoc Advisory Consensus Panel recommends adoption of a new framework or conceptual model for conducting ED outcome trials or clinical research. The concept of 'treatment effectiveness' is proposed as a new 'umbrella concept' or distal outcome to be evaluated.

Macrocephaly-cutis marmorata telangiectatica congenita: seven cases including two with unusual cerebral manifestations

Macrocephaly-cutis marmorata telangiectatica congenita (M-CMTC) is a recently described multiple congenital anomaly/mental retardation (MCA/MR) syndrome of unknown cause. This condition is easily recognizable at birth in children with macrocephaly, cutis marmorata, face and/or body segmental overgrowth, toe syndactyly, midface capillary malformation, and hemimegalencephaly. Cutis marmorata may be absent in some cases. Most patients are developmentally delayed. We describe seven new patients, including two with unusual cerebral manifestations and severe outcome. One of two had a complex congenital heart defect (CHD) and died in the neonatal period. Brain magnetic resonance imaging (MRI) showed generalized cortical dysplasia. The other patient had a stroke episode at age 14 years. Cerebral arteriography showed an abnormal vascular pattern. These findings are consistent with the fact that M-CMTC is a generalized vasculopathy.

Pro-erectile effect of vardenafil: in vitro experiments in rabbits and in vivo comparison with sildenafil in rats

OBJECTIVES

To assess pro-erectile responses to vardenafil, a new selective PDE5 inhibitor, in vitro in isolated rabbit corpora cavernosa, and in vivo in anaesthetized rats.

METHODS

Rabbit cavernosal strips were precontracted with 10 microM phenylephrine. Dose-response relaxation curves to cumulative dosings of vardenafil (1 nM-10 microM) were constructed alone and in the presence of 10 mM L-NAME. Relaxation responses to electrical field stimulation (EFS) (2 Hz, 2 ms, 10 V) were compared in control preparations and in the presence of vardenafil (1-10 nM). Male Sprague-Dawley rats were anaesthetized with urethane and prepared for measurement of blood pressure and intracavernous pressure. Erectile responses (ICPmax/dBP x 100) to cavernous nerve submaximal stimulation (10 Hz, 1 ms, 0.45-1.6 V) were determined before, and 3, 10 and 23 min after i.v. administration of saline, vardenafil or sildenafil (0.1, 1 mg/kg).

RESULTS

Vardenafil was effective in relaxing precontracted rabbit cavernosal strips (IC50 54 +/- 18 nM). This relaxing activity was partially antagonized with 10 mM L-NAME, increasing the IC50 to 620 +/- 81 nM. Vardenafil significantly increased (more than 4 times) relaxation of precontracted rabbit cavernosal strips to EFS at 10 nM. In anaesthetized rats, erectile responses were significantly facilitated 3 and 13 min after 0.1 and 1 mg/kg vardenafil was administered. In contrast, 1 mg/kg sildenafil only significantly increased erectile responses at 3 min post-injection.

CONCLUSIONS

Vardenafil relaxes rabbit corpus cavernosum in vitro and is effective at a lower dose than sildenafil in facilitating erectile responses to cavernous nerve stimulation in anaesthetized rats.

A comparison of the effects of tamsulosin and alfuzosin on neurally evoked increases in bladder neck and seminal vesicle pressure in rats

OBJECTIVE

To assess the effects of the alpha 1-adrenoceptor antagonists alfuzosin and tamsulosin on the physiological events associated with ejaculation in the rat, because when these drugs are used for treating symptomatic benign prostatic hyperplasia in men they may affect ejaculation by impairing bladder neck closure and seminal vesicle contraction.

MATERIALS AND METHODS

In clinical trials the incidence of ejaculatory disorders in men is typically < 1% with alfuzosin and 4-18% with tamsulosin. The effects of tamsulosin and alfuzosin on bladder neck and seminal vesicle pressures (BNP and SVP) in the rat were analysed. Increases in BNP and SVP were induced in urethane-anaesthetized. Wistar rats by electrical stimulation (ES) of the hypogastric nerve (HN) before and after an intravenous injection with vehicle, 3 or 10 micrograms/kg of tamsulosin or alfuzosin (10 rats/group). The mean amplitude and area under the curve (AUC) of the BNP and SVP were expressed as the percentage of the response to ES of HN before the treatment.

RESULTS

The amplitude and AUC of the SVP were significantly decreased by both doses of tamsulosin, and marginally decreased by the same doses of alfuzosin. The amplitude of the BNP was significantly decreased by 3 and 10 micrograms/kg of tamsulosin and 10 micrograms/kg alfuzosin, and marginally decreased by 3 micrograms/kg alfuzosin. The AUC of the BNP was significantly decreased by both doses of tamsulosin, but barely affected by alfuzosin at the same doses.

CONCLUSION

Over the doses assessed, alfuzosin had significantly less deleterious effect on increases in BNP and SVP induced by ES of the HN than had tamsulosin.

Wolfram syndrome in French population: Characterization of novel mutations and polymorphisms in theWFS1 gene

Wolfram syndrome (WS), a rare autosomal recessive neurodegenerative disorder, results in most cases from mutations in the WFS1 gene. In this study, a total of 19 patients with Wolfram syndrome and 36 relatives from 17 families were screened for mutations in the WFS1 gene. WFS1 mutations were identified on both alleles in 16 of 19 patients and on 1 allele of 3 patients, showing that WFS1 is the major gene involved in WS in the french population. We identified 25 different mutations, twelve of which were novel. We found 6 frameshift mutations, 6 nonsense mutations, 6 missense mutations, 6 in-frame deletions, and one new homozygous mutation in the splice donor site of exon 7 (c.861+1G>A) resulting in a frameshift. Most patients were compound heterozygotes. No common founder mutation or mutational hot spot were found in the WFS1 gene. Although most mutations occurred in exon 8, in some cases molecular screening requires analysis of all exons, including the non-coding exon 1. We also identified 3 new polymorphisms. Furthermore, genotype-phenotype correlation suggests that the presence of inactivating mutations on both alleles may be associated with an early onset of diabetes mellitus.

Treatment satisfaction in patients with erectile dysfunction switching from prostaglandin E1 intracavernosal injection therapy to oral sildenafil citrate

Treatment satisfaction, subanalysed by demographic variables, was evaluated in patients switching from successful intracavernosal prostaglandin E(1) (PGE(1)) therapy to oral sildenafil citrate. The validated Erectile Dysfunction Inventory of Treatment Satisfaction questionnaire was administered at the end of PGE(1) therapy and after 12 weeks of sildenafil treatment in a multicentre, open-label study. Men with erectile dysfunction (n=176) who were switched from stable PGE(1) therapy to sildenafil (25-100 mg) were equally satisfied with onset of action, duration of action, and confidence in ability to engage in sexual activity, but expressed greater overall treatment satisfaction with sildenafil (P<0.01), better ease of use (P<0.001), naturalness of erectile process (P<0.001), and intention to continue treatment (P<0.001). Partners (n=32) were overall more satisfied with sildenafil (P<0.05), and their responses correlated with patient satisfaction (r=0.68). Compared with PGE(1) injection, these data suggest that patients may be less likely to discontinue taking sildenafil treatment for their erectile dysfunction.

[Investigation, treatment and monitoring of late-onset hypogonadism in males: the official guidelines of the International Society for the Study of the Study of the Aging Male (ISSAM) with comments]

There is increasing interest in the subject of hormone changes in the aging male, which is likely to become particularly important with the expected growth in the population of men over 50. The main concerns at present are androgen decline in the aging male (ADAM), or partial androgen deficiency of the aging male (PADAM), commonly known as the andropause. Although there have been advances in our knowledge of androgen deficiency in the aging male, it is still incomplete, sometimes confusing, and some aspects of androgen replacement therapy remain controversial. The International Society for the Study of the Aging Male (ISSAM) therefore felt it was a good time to review the current situation by publishing a series of practical and official guidelines concerning the diagnosis, treatment and monitoring of late-onset hypogonadism in males. The aim of this study is to present the French translation of these recent international guidelines, and to comment on them.

alpha(2a) and alpha(2c) adrenoceptors on spinal neurons controlling penile erection

The thoracolumbar and lumbosacral spinal cord contain respectively sympathetic and parasympathetic preganglionic neurons that supply the organs of the pelvis including the penis. These neurons are influenced by supraspinal information and receive aminergic projections from the brainstem. The presence of the alpha(1)- and alpha(2)-adrenoceptor subtypes has been demonstrated in the rat spinal cord. In this species, we looked for the presence of alpha(2a)- and alpha(2c)-adrenoceptor subtypes in the sympathetic and parasympathetic preganglionic neurons controlling erection. In adult male rats, transsynaptic axonal transport of pseudorabies virus injected into the penis was combined with immunohistochemistry against alpha(2a)- and alpha(2c)-adrenoceptor subtypes. At 4 days survival time, neurons infected with the pseudorabies virus were solely found in the intermediolateral cell column and dorsal gray commissure of segment T12-L2 and in the intermediolateral cell column of segment L6-S1. Neurons and fibers immunoreactive for alpha(2a)- and alpha(2c)-adrenoceptor subtypes were mainly present in the intermediolateral cell column, the dorsal gray commissure and the ventral horn of the T12-L2 and L5-S1 spinal cord, the dorsal horn displayed only immunoreactive fibers. Pseudorabies virus-infected neurons in the autonomic nuclei were both immunoreactive for alpha(2a)- and alpha(2c)-adrenoceptor subtypes and closely apposed by alpha(2a)- and alpha(2c)-immunoreactive fibers. The results suggest an intraspinal modulation of the noradrenergic and adrenergic control of the autonomic outflow to the penis by pre- and postsynaptic alpha(2) adrenoceptors.

Selegiline enhances erectile activity induced by dopamine injection in the paraventricular nucleus of the hypothalamus in anesthetized rats

Apomorphine delivered in the paraventricular nucleus of the hypothalamus (PVN) induces penile erection in rats, suggesting a role of dopaminergic projection to the PVN in the control of penile erection. We assessed whether the selective inhibitor of monoamine oxidase B, selegiline, could enhance the erectile activity induced by dopamine delivery in the PVN. Intracavernous and blood pressure (ICP and BP) were monitored in anesthetized rats to quantify ICP rises (number and percentage of ICP maximum/mean BP (ICPmax/BP x 100)) elicited by 10 micro g dopamine injection in the PVN after saline or 3 mg/kg i.v. selegiline (8 rats per group). The number of ICP rises (mean+/-s.d.: 4.5+/-2.9 vs 1.4+/-1.9; P=0.017) and their ICPmax/BP x 100 (49+/-8% vs 34+/-9%; P=0.015) were significantly greater upon dopamine injection in the PVN than upon vehicle. Compared to saline i.v., 3 mg/kg selegiline pretreatment significantly increased the number of ICP rises induced by dopamine injection in the PVN (9.4+/-2.6 vs 4.5+/-2.9; P<0.001), without affecting their amplitude. This suggests that drugs potentiating dopaminergic responses in the central nervous system might enhance proerectile commands of supraspinal origin.

Evidence for a direct projection from the paraventricular nucleus of the hypothalamus to putative serotoninergic neurons of the nucleus paragigantocellularis involved in the control of erection in rats

In the male rat, serotoninergic neurons of the ventrolateral medulla send direct projections onto spinal preganglionic neurons that innervate the penis. The role of the paraventricular nucleus of the hypothalamus in the control of penile erection is well recognized. Our aim was to demonstrate anatomical relation between paraventricular neurons and medullary serotoninergic neurons innervating the penis. In adult male rats, stereotaxic iontophoretic injections of Phaseolus vulgaris leuco-agglutinin were performed in the paraventricular nucleus. Neurons in the ventrolateral medulla were retrogradely labelled using transneuronal retrograde transport of pseudorabies virus injected in the corpus cavernosum. Sections of the ventro-lateral medulla were processed for double immunofluorescence to reveal both Phaseolus vulgaris leuco-agglutinin and pseudorabies virus using specific antibodies. Sections were also processed for the simultaneous detection of pseudorabies virus and serotonin. Pseudorabies virus-infected neurons in the ventrolateral medulla were present in the nucleus paragigantocellularis, reticular formation of the medulla, raphe pallidus and raphe magnus. In the nucleus paragigantocellularis, all pseudorabies virus-infected-neurons were immunoreactive for serotonin. Some of them received Phaseolus vulgaris leuco-agglutinin-labelled varicose fibres that ran along the soma of pseudorabies virus-infected neurons. Confocal microscopy suggested the presence of several close appositions between them, which were demonstrated using three-dimensional reconstruction of serial optical sections. Our results show that paraventricular neurons send direct projections in the nucleus paragigantocellularis onto neurons that innervate the penis. They suggest a possible role of the paraventricular nucleus in penile erection through the control of descending serotoninergic raphe-spinal neurons. The neurotransmitter used in this pathway remains to be determined.

Catecholaminergic projections onto spinal neurons destined to the pelvis including the penis in rat

In rats, the spinal cord contains proerectile autonomic motoneurons destined to the penile tissue and its vasculature, and somatic motoneurons destined to the perineal striated muscles. It receives dense catecholaminergic projections issued from the medulla and pons. In adult male rats, we evidenced the catecholaminergic innervation of spinal neurons controlling lower urogenital tissues and regulating penile erection. We combined retrograde tracing techniques and immunohistochemistry against synthetic enzymes of noradrenaline and adrenaline. Both sympathetic and parasympathetic preganglionic neurons, labeled from the major pelvic ganglion or from the corpus cavernosum, were apposed by catecholaminergic immunoreactive fibers. Motoneurons, retrogradely labeled from the striated muscles, were also apposed by catecholaminergic immunoreactive fibers. Synapses between these motoneurons and fibers were suggested by confocal microscopy and confirmed by electron microscopy in some cases. The results reinforce the hypothesis of a catecholaminergic control of autonomic and somatic motoneurons regulating penile erection at the spinal level.

Apomorphine SL (Uprima): preclinical and clinical experiences learned from the first central nervous system-acting ED drug

An exclusive central site of action for the proerectile effect of apomorphine, including not only the brain but also the spinal cord, is supported by extensive experimental data. Assuming that the mechanisms of action of apomorphine are similar in humans and animal models, its use for the treatment of erectile dysfunction (ED) validates the emerging idea that erectile response could be enhanced by acting directly within the central nervous system (CNS). It also emphasized the key role of the dopaminergic system in the control of erection. As exemplified with the clinical development of apomorphine, targeting the CNS does not rule out the occurrence of undesirable side effects. Because the rare event of syncope induced by apomorphine is not well understood, further research should be conducted to explore its possible mechanisms. In clinical practice, however, approved doses of apomorphine SL are well tolerated. It is noteworthy that no modification of sexual desire was observed with apomorphine. Indeed, drugs acting within the CNS may more likely interact with sexual desire than peripherally acting drugs, and care should be taken to assess this point in the future. Although our knowledge of the control of penile erection by the CNS is restricted, there are many potential sites for CNS-acting ED drugs. New centrally acting therapy for ED should concentrate on receptor targets more specific to erectile command. Clinical efficacy of new centrally-acting compounds will assess the well-founded purpose of this rationalization.

Efficacy results and quality-of-life measures in men receiving sildenafil citrate for the treatment of erectile dysfunction

The aim of the present study was to evaluate the efficacy of sildenafil citrate and its effects on quality of life (QoL) in men with erectile dysfunction (ED) using data from three multicenter, double-blind, placebo-controlled clinical trials. Efficacy was evaluated using a global efficacy question (improvement of erections) and questions from the International Index of Erectile Function (IIEF) addressing the ability to achieve and maintain erections. QoL directly related to ED was evaluated using questions 13 and 14 of the IIEF, several psychometric instruments, and a questionnaire addressing men's concerns about their erection problems. Seventy-nine [corrected] percent of patients receiving sildenafil reported improved erections compared with 23% of patients receiving placebo (p < 0.0001); also reported were improvements in the ability to achieve and maintain erections with sildenafil but not with placebo (p < 0.0001). Improvements were also seen for other aspects of sexual function (overall satisfaction with sex life, sexual relationships with partners, concerns about erectile problems, p < 0.0001) and general mental health (well-being, self-control, satisfaction with relationship, health relative to 1 year ago, mental health; p < or = 0.05) following treatment with sildenafil. Thus, treatment of ED with sildenafil can significantly improve key QoL parameters related to sexual dysfunction and general mental health.

Central nervous system agents in the treatment of erectile dysfunction: how do they work?

Drugs acting within the central nervous system (CNS) that reduce the sympathetic antierectile flow and enhance the parasympathetic proerectile flow to the penis may restore penile erection in cases of erectile dysfunction of both psychogenic and organic origin. The best characterized of such drugs is the dopaminergic agonist apomorphine, which acts on the hypothalamus and, perhaps, the autonomic nuclei in the spinal cord. Other drugs that target the CNS and have been registered and tested are the a(2)-adrenoceptor antagonists yohimbine and delequamine, the alpha-melanocyte-stimulating hormone agonist melanotan II, and the serotonin reuptake inhibitor trazodone. Androgens also may influence sexual behavior by acting within the CNS, notably by modifying the neurotransmitter system targeted by these drugs. Our knowledge of the mode of action of CNS drugs comes mainly from experiments on rodents. Consequently, explanations regarding the way they work in humans are only speculative.

Sodium salicylate inhibits prostaglandin formation without affecting the induction of cyclooxygenase-2 by bacterial lipopolysaccharide in vivo

The mechanisms underlying the anti-inflammatory properties of salicylate are not well understood. In particular, while salicylate inhibits prostaglandin production in vivo it only weakly inhibits cyclooxygenase (COX)-1 or -2 activity in vitro. Thus, it has often been suggested that in vivo salicylate may inhibit the expression rather than the activity of COX, particularly COX-2. Using a model of acute COX-2 expression in the rat, we show that salicylate inhibits COX-2 activity in vivo without affecting COX-2 expression. In anesthetized rats LPS (6 mg kg(-1), i.p.) increased the expression of COX-2 as evidenced by increased circulating levels of 6-keto-prostaglandin F(1alpha) (6-keto-PGF(1alpha), a stable breakdown product of PGI(2)), greatly exaggerated formation of 6-keto-PGF(1alpha) following arachidonic acid (AA) challenge (3 mg kg(-1), i.v.), and increased expression of COX-2, but not COX-1, protein. Diclofenac (3 mg kg(-1), i.p.) or the COX-2 selective agent diisopropyl fluorophosphate (10 mg kg(-1), i.p.) decreased the LPS-induced increase in circulating 6-keto-PGF(1alpha) and the exaggerated 6-keto-PGF(1alpha) production following AA challenge. Sodium salicylate (20 or 120 mg kg(-1), i.p.) (administered either 1 h prior, or once per day for 3 days prior, to LPS injection) reduced only the LPS-induced increase in circulating 6-keto-PGF(1alpha), but not the exaggerated 6-keto-PGF(1alpha) production following AA challenge or the expression of COX-2. Thus, salicylate inhibits LPS-induced COX-2 activity in a manner that is overcome by provision of excess substrate and independent of effects on COX-2 expression. In conclusion, our results exclude mechanisms other than direct enzyme inhibition as responsible for the anti-COX effects of salicylate.

Dopamine and male sexual function

The use of the D1/D2 dopamine receptor agonist apomorphine for the treatment of erectile dysfunction provides strong support in favor of a participation of the dopaminergic system in the control of sexual function. However, the exact involvement of dopamine in the control of sexual motivation and genital arousal in males is unknown. Experimental data in male rats suggested an implication of dopamine in sexual motivation as well as in copulatory performance. Specific tests allowing assessment of sexual motivation showed that the release of dopamine at the level of the nucleus accumbens (innervated by the mesolimbic dopaminergic pathway) and the medial preoptic area of the hypothalamus (innervated by the dopaminergic incertohypothalamic pathway) positively regulated the anticipatory/motivational phase of copulatory behavior. A permissive role of dopamine released at the level of the median preoptic area of the hypothalamus in the display of copulatory behavior has also been demonstrated. It is noteworthy that these participations of the dopaminergic system are not specific for sexual behavior but rather reflect the involvement of dopamine in the regulation of cognitive, integrative and reward processes. Because of its role in the control of locomotor activity, the integrity of the nigrostriatal dopaminergic pathway is also essential for the display of copulatory behavior. Somehow more specific to sexual function, it is likely that dopamine can trigger penile erection by acting on oxytocinergic neurons located in the paraventricular nucleus of the hypothalamus, and perhaps on the pro-erectile sacral parasympathetic nucleus within the spinal cord. In conclusion, central dopamine is a key neurotransmitter in the control of sexual function.

Cyclooxygenase selectivity of non-steroid anti-inflammatory drugs in humans: ex vivo evaluation

We have recently described a novel assay to assess ex vivo the activity and selectivity on cyclooxygenase-1 and -2 (EC 1.14.99.1) of non-steroid anti-inflammatory drugs (NSAID) administered to rats [Br. J. Pharmacol. 126 (1999) 1824.]. Here, we have extended these studies to humans. Healthy male volunteers were given orally one of the following drugs (mg) for 5 days: etodolac (200 or 400 b.i.d.), meloxicam (7.5 or 15 q.d.), nimesulide (100 or 200 b.i.d.), nabumetone (500 or 1000 b.i.d.) or naproxen (500 b.i.d.). Blood samples were withdrawn from the volunteers before and up to 24 h after the last dose. Plasma obtained from the blood was tested for its ability to inhibit prostanoid formation in interleukin-1beta-treated A549 cells (cyclooxygenase-2 system) and human washed platelets (cyclooxygenase-1 system). Plasma from etodolac-treated subjects demonstrated a slight selectivity towards the inhibition of cyclooxygenase-2. This effect was more prominent in plasma from subjects receiving meloxicam or nimesulide. Plasma from nabumetone-treated subjects showed no or little selectivity towards cyclooxygenase-1 depending on the dose of drug administered, while plasma taken from subjects receiving naproxen was more active at inhibiting cyclooxygenase-1 than cyclooxygenase-2. In conclusion, we have demonstrated that this assay can be used to assess ex vivo the relative activity against cyclooxygenase-1 and cyclooxygenase-2 of NSAIDs consumed by human volunteers. It is to be hoped that data from such systems will aid in our understanding of the relationships between the differential inhibition of cyclooxygenase-1 and cyclooxygenase-2 by NSAIDs and their reported efficacies and (gastrointestinal) toxicities.

The efficacy and tolerability of vardenafil, a new, oral, selective phosphodiesterase type 5 inhibitor, in patients with erectile dysfunction: the first at-home clinical trial

Vardenafil, a novel selective phosphodiesterase type 5 inhibitor, was evaluated in its first large-scale at-home trial. A total of 601 men with mild to severe erectile dysfunction (ED) were enrolled in this multi-centre, randomized, double-blind, placebo-controlled trial of 12 weeks of treatment with either placebo or 5, 10 and 20 mg of vardenafil. Primary endpoints were Q3 (vaginal penetration) and Q4 (maintenance of erection) of the International Index of Erectile Function (IIEF). In the intent-to-treat population (n=580), the changes from baseline for 5, 10 and 20 mg vardenafil (1.2, 1.3 and 1.5, respectively) were all improved (P<0.001) over placebo (0.2) for Q3 and were similarly improved for Q4 (1.4, 1.5 and 1.7) compared to placebo (0.5) (P<0.001). All vardenafil doses improved all IIEF domains compared to placebo (P<0.001). The percentage of successful intercourses was between 71 and 75% for the three vardenafil doses. For the 20 mg dose, 80% of the patients experienced improved erections (GAQ) compared to 30% for placebo. Most frequent treatment-emergent adverse events were headache (7-15%), flushing (10-11%) and up to 7% for dyspepsia or rhinitis. Vardenafil treatment resulted in a high efficacy and low adverse-event profile in a population with mixed ED etiologies.

Dopamine and sexual function

The use of the D1/D2 dopamine receptor agonist apomorphine SL for the treatment of erectile dysfunction provides a strong support in favour of a participation of the dopaminergic system in the control of sexual function. However, the exact involvement of dopamine in sexual motivation and in the control of genital arousal in humans is unknown. In contrast, experimental data suggest an implication of dopamine at all these stages of the copulatory behaviour in rodents. The release of dopamine at the level of the nucleus accumbens, which is innervated by the mesolimbic dopaminergic pathway originating in the ventral tegmental area, is positively implicated in the pre-copulatory or appetitive phase in male rats. There is also a permissive role in the copulatory or consumatory phase for dopamine released at the level of the median pre-optic area, which receives projection from the dopaminergic incertohypothalamic pathway within the hypothalamus. It is noteworthy that these participations of the dopaminergic system are not specific to sexual behaviour but rather reflect the more general involvement of dopamine in the regulation of cognitive, integrative and reward processes. Due to its role in the control of locomotor activity, the integrity of the nigrostriatal dopaminergic pathway is also essential for the display of copulatory behaviour. Somehow more specific to sexual function, it is likely that dopamine can trigger penile erection by acting on oxytocinergic neurons located in the paraventricular nucleus of the hypothalamus, and perhaps on the pro-erectile sacral parasympathetic nucleus within the spinal cord. The counterpart of such regulation of the genital arousal by dopamine has not yet been established in females. In conclusion, the central dopaminergic system is a key element of the control of sexual function.

Vaginal physiological changes in a model of sexual arousal in anesthetized rats

The understanding of the pathophysiology of female sexual dysfunction suffers from the lack of a convenient model for the study of female genital sexual response. In this study, systemic arterial blood pressure (BP) as well as partial oxygen tension, temperature, and blood engorgement of the vagina [using laser-Doppler flowmetry in arbitrary units (AU)] were measured in anesthetized, ovariectomized (1 wk before the start of the experiment) female rats. Vaginal sexual arousal was replicated by electrical stimulation of the pelvic nerve (PNS). PNS induced reproducible increases in the different vaginal parameters (from baseline value, respectively: 16 +/- 10 to 30 +/- 12 mmHg; 34.9 +/- 0.6 to 36 +/- 0.6 degrees C; 450 +/- 196 to 1,500 +/- 360 AU; P < 0.05, paired t-test) and BP (90 +/- 7 to 123 +/- 13 mmHg, P < 0.05, paired t-test). Vaginal vascular resistance was significantly decreased during PNS (from 0.23 +/- 0.15 to 0.08 +/- 0.02 mmHg/AU). Vaginal wall tension was also measured with a force transducer. PNS induced an increase in vaginal wall tension (1.0 +/- 0.2 g), followed by a decrease under the prestimulation value. Intravenous atropine sulfate (1 mg/kg) injection abolished the increase in vaginal wall tension without significantly affecting vaginal vascular resistance. Intravenous vercuronium bromide (2 mg/kg) injection abolished the decrease in vaginal wall tension. Concomitant electrical stimulation of the paravertebral sympathetic chain inhibited vaginal response induced by PNS. Electrical stimulation of the medial preoptic area of the hypothalamus induced a response qualitatively equivalent to PNS with a significant decrease of vaginal vascular resistance. These data support that vaginal contractions involve both smooth and striated muscles and indicate that neural control of vaginal sexual arousal have great similarities in male and female rats.